1.Poliovirus in smallest area ever: only 4 countries remain that have never stopped polio before.
根除脊髓灰质炎病毒在历来最小的地区:只剩4个国家从未制止脊髓灰质炎。
2.Poliovirus in smallest area ever: only 4 countries remain that have never stopped polio before.
根除脊髓灰质炎病毒在历来最小的地区:只剩4个国家从未制止脊髓灰质炎。
3.This means by the time a paralytic case is found, the poliovirus has probably spread.
这就意味着,当瘫痪病例被发现时,小儿麻痹症病毒已经扩散了。